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Tuesday, December 07, 2004

Anderson Exam II w\answers

1) In order for a colony to be visible to the naked eye, about how many cells must be present?
_a) 1,000,000
_b) 100,000
_c) 10,000
_d) 1,000

2) The simplest technique for isolating bacteria in growth media is referred to as the
_a) pour plate method
_b) streak plate method
_c) serial dilution method
_d) MPN method

3) The solidifying agent used most successfully in bacterial nutrition media is
_a) gelatin
_b) peptone
_c) agar
_d) starch

4) Prokaryotic cells divide by a process known as
_a) conjugation
_b) mitosis
_c) binary fussion
_d) binary fission

5) In the growth curve of a bacterial population, the bacteria are rapidly increasing in number in the
_a) lag phase
_b) exponential log phase
_c) stationary phase
_d) decline phase
_e) boomer phase

6) A hot tub would most likely contain
_a) psychrophiles
_b) partiers
_c) thermophiles
_d) mesophiles

7) The optimal temperature for most human pathogens might be expected to range from
_a) 35 to 40° C
_b) 20 to 45° C
_c) 15 to 25° C
_d) 93 to 98.6° C

8) Bacteria on fish caught in the Arctic Ocean would
_a) be psychrophiles
_b) be mesophiles
_c) continue to grow while the fish is in the refrigerator
_d) not grow very well in the refrigerator
_e) A and C

9) Organisms that are indifferent to the presence of oxygen and do not use it are
_a) aerotolerant anaerobes
_b) facultative anaerobes
_c) obligate aerobes
_d) microaerophiles

10) Mycobacterium lepre is typically found infecting the ears, toes and fingers of its hosts due to its
_a) requirements for well-oxygenated blood
_b) easy access to those parts
_c) need for cooler temperatures
_d) long incubation period

11) High concentrations of salt and sugar in foods
_a) are useful in preserving the food
_b) tend to draw water out of a cell
_c) tends to force water into a cell, causing plasmolysis
_d) have no effect on water availability
_e) A and B

12) The prefix photo- indicates that an organism will make use of
_a) chemicals
_b) organics
_c) light
_d) inorganics

13) Growth factors are
_a) compounds that must be synthesized by the organism
_b) compounds that must be provided to the organism
_c) physical factors such as temperature
_d) inorganic molecules

14) An organism called Bacillus fastidiosus
_a) might be expected to be very flexible as to growth requirements
_b) might be expected to be very strict as to its growth requirements
_c) would probably be grown on a chemically defined media
_d) might be expected to have a rod shape
_e) B, C and D

15) A medium that inhibits the growth of organisms other than the one being sought is termed
_a) synthetic medium
_b) specific culture medium
_c) selective medium
_d) enrichment medium

16) A sterile item is free of
_a) microbes
_b) endospores
_c) viruses
_d) prions
_e) A, B and C

17) Pasteurization
_a) is the use of heat to sterilize food products
_b) is the use of heat to reduce pathogenic spoilage bacteria to a safe level
_c) is a process which uses intense cold to kill microorganisms on foods
_d) is a process which uses short bursts of radiation to kill microorganisms on foods

18) Typical conditions used for sterilization are
_a) 100° C for 10 minutes
_b) 121° C at 15 psi for 15 minutes
_c) 80° C for 15 minutes
_d) 72&#176 C for 15 seconds

19) Which of the following is not a sterilization method
_a) hot air oven
_b) autoclave
_c) pasteurization
_d) filtration

20) Chemical germicides
_a) may react irreversibly with proteins and enzymes
_b) may react with cytoplasmic membranes or viral envelopes
_c) may be disinfecting or sterilizing
_d) are sensitive to dilution factors, time of contact, and temperature of use
_e) all of the above

21) Which of the following is true of hydrogen peroxide
_a) it is a sterilant for inanimate objects and is quickly inactivated on human tissue
_b) it leaves a toxic residue
_c) it is broken down by catalase into water and oxygen
_d) it is even more effective when used in combination with peracectic acid
_e) A, C and D

a.) sterilization (b) disinfection (c) pasteurization (d) sanitation (e) antiseptic

22) eliminates most pathogens on a material or surface

23) for use on the skin

24) reduction of microorganisms to meet health standards

25) use of heat to eliminate pathogens and spoilage of organisms

26) removal of all pathogens including endospores but not prions

27) Organic acids, such as benzoic acid, are often added to foods to prevent microbial growth

28) Boiling is very effective at removing most common waterborne pathogens

29) Pasteurization results in the sterilization of food products

30) The strands of DNA are bonded to one another by
_a) covalent bonds
_b) oxygen bonds
_c) hydrogen bonds
_d) carbon bonds

31) Which pairing is incorrect
_a) A:T
_b) G:C
_c) A:U
_d) A:G

32) RNA is characterized by
_a) deoxyribose
_b) thymine
_c) ribose
_d) double-stranded

33) DNA is characterized by
_a) ribose
_b) single stranded
_c) deoxyribose
_d) thymine
_e) C and D

34) How many nucleotides are in a codon
_a) 1
_b) 2
_c) 3
_d) 4
_e) 5

35) There are _____ possible codons to code for the 20 possible amino acids
_a) 20
_b) 30
_c) 64
_d) 61

36) tRNA functions to
_a) transfer an amino acid to mRNA
_b) transcribe the mRNA
_c) terminate the proteins on the mRNA
_d) transribe the genetic code on rRNA

37) Gene regulation may entail
_a) turning on genes only when needed
_b) turning off genes when not needed
_c) turning on or off entire groups of genes
_d) all of the above

38) The source variation among microorganisms that were once identical is
_a) antibiotic resistance
_b) virulence factors
_c) sigma factors
_d) mutation

39) Irradiation of cells with ultraviolet light may cause
_a) 4 nucleotides covalently bonding together
_b) thymine dimers
_c) adenine complementary base pairing with cytosine
_d) the addition of uracil

40) Which would have the least effect on the amino acid sequence
_a) addition of 1 nucleotide
_b) deletion of 2 consecutive nucleotides
_c) addition of 2 nucleotides
_d) addition/deletion of 3 consecutive nucleotides
_e) A and C

41) The largest group of chemical mutagens consist of
_a) radiation
_b) base analogs
_c) nitrous acid
_d) alkylating agents

42) Chemical mutagens that mimic the naturally occurring bases are called
_a) nitrogen mustards
_b) alkylating agents
_c) base analogs
_d) nitrous oxide

43) Three-ringed planar molecules used as chemical mutagens are called
_a) nitrous oxide
_b) base analogs
_c) alkylating agents
_d) intercalating agents

44) Segments of DNA capable of moving from one area in the DNA to another are called
_a) Base analogs
_b) intercalating agents
_c) transposons
_d) palindromic sequences

45) On which strand would UV radiation have the most effect
_d) B and C

46) Thymine dimers are dealt with by
_a) no repair mechanisms
_b) dimer repair
_c) SOS repair
_d) endonuclease repair

47) The mechanism by which genes are transferred into bacteria via viruses is called
_a) ellipsis
_b) replica plating
_c) transformation
_d) transduction
_e) conjugation

48) In conjugation, the donor cell is recognized by the presence of
_a) an F plasmid
_b) a Y chromosome
_c) diploid chromosomes
_d) an SOS response
_e) A and C

49) Gene transfer that requires cell to cell contact is
_a) transformation
_b) conmpetency
_c) conjugation
_d) functional genomics

50) Which is true of DNA replication
_a) it is semiconservative
_b) it starts at an origin of replication
_c) it is bi-directional
_d) it requires RNA primers
_e) All are correct


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